There are many recognized methods of joining large timbers together to form various structures. For instance, barns and houses built in New England have used tongue and grooves cut from the wood to maintain rigidity of the structure. Log cabins typically gain structural rigidity by the use of generally flat-sided logs having interconnecting notches near the vertical edges of the building. Cross-posts between vertical posts on wooden fencing are often joined by toe-nails, support blocks, or simple L-shaped brackets.
Another more sophisticated joint for jointing straight segments of a dome-shaped structure is disclosed in U.S. Pat. No. 3,635,509 to Birkemeier et al, issued Jan. 18, 1972. The disclosed structure includes a number of beams connected together in triangles by bolted joints. The joints each have a pair of straps bolted to the ends of the beams. Other bolts in the straps pass through clearance notches which are welded in the ends of a short section of tubing. These additional bolts pass through and bear against the inner periphery of the tube.
The straps connected to the wooden beams as disclosed in Birkemeier et al are not U-shaped and consequently lack the structural integrity found in the instant invention.
Another geodesic dome using flat straps to connect its integral wooden beams is disclosed in U.S. Pat. No. 4,260,276 to Phillips, issued Apr. 7, 1981. Six sets of paired flat straps are welded to a tapered hexagonal ring. Each pair of straps is bolted through a timber so that the timber butts against the ring. Six timbers are joined at the hexagonal ring.
Phillips does not suggest the use of a shallow U-shaped channel in contact with the timbers nor does it disclose a support frame such as the one integral in this invention.
A final timber connector used to connect the wooden joists making up a geodesic dome is disclosed in U.S. Pat. No. 4,262,461 to Johnson et al, issued Apr. 21, 1981. The Johnson connector is made up of a central metal sleeve or cylinder having six pairs of circumferentially spaced openings and a set of six tongue members which are bolted to the ends of the timbers. The tongue members have flat sides and the attaching bolts pass through both flat sides and the timber. Each tongue member has a pair of protrusions at the end of the timber which pass through two of the openings in the central metal sleeve. A tapered pin is inserted through each sleeve member protrusion as it passes through the sleeve. The pin holds the timber in place.
Johnson et al does not suggest the use of shallow U-shaped channels in contact with the timbers nor any other part of the disclosed invention.
The disclosure in U.S. Pat. No. 4,318,628 to Mancini, issued Mar. 9, 1982, shows a device for joining wooden panels. The devices each use a number of joined deep U-shaped channels having spikes placed at the bottom of each channel. The channels may be joined at, e.g., 90.degree. angles so that when panels are inserted into those channels, the panels meet at 90.degree..
Mancini does not suggest using a pair of shallow U-shaped channels bolted on the opposite sides of a large timber. The Mancini device does not use a supporting framework to position and hold the channels.
None of the timber joining devices shown in the prior art discloses or suggests the devices claimed herein nor any portion of those devices.